Geography 316:  BiogeographyIn progress 5/14/99

The Biogeography of the European Bison
(Bison bonasus bonasus)
 

by Donald Patterson, student in Geography 316
 

Photo Source: J.Krasinski

Kingdom -- Animalia
Phylum -- Chordata
Class -- Mammalia
Orders -- Artiodactyla
Family -- Bovidae
Genus -- Bison
Species -- bonasus
Subspecies -- bonasus

Natural History:
The European bison (Bison bonasus), also called the wisent, and zubr (zshoobr) in Poland, once roamed the great temperate, deciduous forest biome that stretched from the British Isles, through most of Europe and into Siberia (PHVA, 1999). Though, time has taken its toll on the once continuous distribution of bison, which now exist in few isolated areas. There are two subspecies – the lowland bison (Bison bonasus bonasus) and the highland or Caucasus bison (Bison bonasus caucasus), yet there are no remaining pure Caucasus stock-- they were intermixed with lowland bison and, in some cases, the American bison (Bison bison) before they went extinct in the wild. The original distribution consisted of three subspecies, but today only the lowland pedigree and Caucasus hybrid remains. The herds are managed as two separate lineage and kept isolated to prevent interbreeding. The lowland bison today consists of about 1,000 animals, with 69% free ranging in Poland, Belarus, Russia, Lithuania, Romania, and Ukraine. The others exist in zoos, private preserves, and breeding stations. The Caucasus subspecies is made up of about 2,200 animals, roughly half of which are wild. (PHVA, 1999). For practical purposes the remainder of this paper will consider only the lowland subspecies.

The largest concentration of European bison live in Poland's Bialowieza National Park (Falinski, 1999). It is here that Europe's last remaining primeval forest stands. The National Park covers an area of about 20-square miles, which is located within the larger (and lesser protected) Bialowieza forest – 220sq.mi., and is contiguous to Belarus’ Beloveskaja Pusca National Park – 335sq.mi (WCMC, 1999) .

The ancient forest lies in a flat, moist region consisting of 26 species of trees, 55 species of shrubs, 14 species dwarf shrubs, and 62 species of mammals, of which wolves and lynx are important predators of young and weak bison. These are a few of the over 10,000 species that contribute to the forest’s rich biodiversity (Falinski, 1999). Some of the trees include oak, lime, hornbeam, ash, maple, elm, pines, firs, alder, willow, birch and aspen. This dense, climax forest is interspersed with ecosystems of marsh, peat bog, meadow, and thicket. (Falinski, 1999).

The herbivorous bison are mostly browsers, but can graze where grasses are available. As primary consumers they browse on a wide range of deciduous trees, shrubs, and heathers, and on evergreen trees and shrubs in the winter (Falinski, 1999). Their diets include leaves, twigs, young shoots, bark and berries of over 374 different plants (Riccuiti, 1973). Their favorite plants include willow, aspen, ash, mistletoe, and blackberry. They also eat mushrooms, ferns, lichens, mosses, and acorns (Krasinski,1990). Because the bison's range is restricted by man-made barriers within forest boundaries, park wardens supplement the animal's diet in winter with hay, oats, and sugar beets (Hinrichsen, 1990).

The European bison is the largest mammal on the continent. Large bulls can stand over 6 feet tall, be longer than 9 feet, and weigh over 2,000 lbs. Males are larger than the females, but both sexes have short horns (TUUP, 1999.). A thick shaggy mane covers the head and neck, and in the autumn the bison put on an extra thick coat of hair to ready themselves for the winter, where temperatures in January average 25 F, and snow cover persists, on average, 92 days a year (Falinski, 1999).

The female bison usually live in herds of around twenty to thirty animals (Burton & Pearson, 1987). Herd sizes vary due to their seasonal cycles – breeding, calving, and chance encounters with other groups determine the number in a group (Krasinski,1990). During the calving season, which usually lasts from May to July, cows leave the herds and give birth to one calf, sometimes two (Riccuiti, 1973). Gestation period for the cows last between 254-272 days (TUUP, 1999). Within days of the birth, calves are on their feet. Weaning lasts from four to six months. The female calves will reach sexual maturity in about two years, while the males at about eight years. Bison can live to be over twenty-five years old (TUUP, 1999).

During the winter months the cows and their calves congregate into larger herds, where they gather at two remote feeding stations. Although the bison gather in larger herds in the winter, each animal acts on its own, with little coordination in their activities. (Krasinski,1990). Some of the older bulls form small herds, but most bulls keep to themselves. In historical times, winter served as an aid in the natural selection process, as the scarcity of food and colder weather weeded out weaker animals. Some scientists also believe the bison may have migrated south to warmer regions during the harshest winters.

Large mating bulls live most of the year alone. During the mating season, which begins in August and lasts through October, the bulls come in from the forest and join the herds of cows and their calves to commence the rut. The strongest and largest bulls go head to head, and square off by pushing their massive heads into their opponents until one is badly injured or tires (Hinrichsen, 1990). Each breeding bull then gathers herds of twelve cows or more and remains with them until the end of mating season, at which time they return to their solitary lives (Krasinski, 1990).

Evolution:
The earliest fossil records for mammals date back around 230 million years ago, to the late Triassic-early Jurassic period. In the beginning of evolution from its reptile ancestors, mammals were small and shrew or mouse-like. Mammals remained small throughout the Mesozoic Era as dinosaurs dominated the Earth. With the calamitous events that brought the extinction of the dinosaurs some 65mya, mammals began their adaptive radiation into the many vacated niches. During this late Cretaceous Period, mammals would begin their ascension toward becoming the most dominant land animals. (Savage & Long, 1986).

Today, one third of all mammal genera are herbivores, and more than half belong to two orders—Perissodactyla, meaning odd-toed, and Artiodactyla, meaning even toed (Savage & Long, 1986). These ungulates, with the other four members of this group, have hooves, or specialized nails, as an adaptation for running (TUUP, 1999).

The artiodactyl’s foot axis is between the 3^rd and 4^th digit, which are usually equal in size. This anatomical adaptation allowed for the limbs to elongate, especially the feet. These changes, along with the fusion of paired limb bones and alteration in the ankle joints, allowed ungulates to exploit a wide variety of terrains and escape predators quickly. The astralagus, or ankle bone, gives increased flexibility to the foot and aids springing action (Savage & Long, 1986). As an example, bison can run over twenty-five miles per hour, and can jump a tenet stream or a six-foot tall fence from a standing position (Hinrichsen, 1990).

Three other important adaptations in some of the hoofed herbivores include a more complex four chambered stomach, skull outgrowths, and modified dentition. In the Artiodactyla suborder Pecora (giraffes, deer and cattle), the stomachs of these higher ruminants have four chambers—the rumen, reticulum, osmasum, and abomasum. It allows for the digestion of tough cellulose fibers. Microorganisms break down the food in the first two chambers, which is regurgitated and chewed as cud. It is then redigested through the last two stomach chambers and passed to the intestines. The fermenting process of the rumen facilitates efficient consumption of food, and at the same time allows the animal to spend more time resting while digesting its food, which decreases vulnerability to predators. The skull outgrowths of bison and others in the Bovidae family, are used both for defensive and offensive purposes. Both sexes have horns-- they are permanent, and never branch. The giant bison, Bison latifrons, from the late Pleistocene of southwest United States had horns over 7-feet long, compared to about 25-inches in the bison today. The teeth of the suborder Pecora have reduced canines or they are absent. The upper molars have four crescentic cusps, which vary mainly in height. Bovoids have higher crowned teeth than the deer and giraffe because of the different foods they eat. (Savage & Long, 1986).

The Bovoids are composed of two families—the antilocaprids, with the pronghorn of North America as its only representative, and the bovids of the Old World, which are represented by cattle, sheep, goats, antelope, gazelles, buffalo, and bison to name a few. Their family goes back to Miocene times, around 20-million years ago. During this period roughly fifteen genera existed, most being from Asia. By the late Miocene, some 10-mya, there are seventy new bovid genera, and by the Pleistocene, there were over one hundred. Today, there is about half that number. (Savage & Long, 1986).

It is presumed the family evolved from the tropical regions of the world. Only in the mid-Pleistocene do bovids appear to have adapted to cold, northern climates and migrated across Beringia into the New World (Savage & Long, 1986). The American bison (Bison bison) is a close cousin of The European bison. Scientists believe both species descend from an ancient relative in India. As the herds traveled north from India, some went east into Siberia and eventually crossed the Bering land bridge into the New World, while other members of the herd headed west into the European forests. Bison priscus, the immediate ancestor of the European bison went extinct, during the last glaciation. (Riccuiti, 1974).

Some scientists believe the European bison was at one time a grazer. During the Ice Ages of the Pleistocene epoch, much of Europe and Asia was covered by glaciers. The remaining landscape consisted of steppes. The European bison, or its immediate ancestor, Bison priscus, lived on these grassy plains. As the glaciers retreated, much of the steppes were replaced by forests, and it is thought that the European bison adapted to its new environment by becoming a browser.
 
 

Distribution
The lowland bison today consists of about 1,000 animals, with 69% free-ranging in Poland, Belarus, Russia, Lithuania, Romania, and Ukraine. The others exist in zoos, private preserves, and breeding stations. The Caucasus subspecies is made up of about 2,200 animals, roughly half of which are wild. (PHVA, 1999). For practical purposes the remainder of this paper will consider only the lowland subspecies.
 

Other interesting issues:
TIMELINE OF ..
20,000 years ago – Lascaux and Chauvet cave paintings; two of the many by Cro-magnon man, reveal ancient relationship between man and bison, which were long hunted for meat and hides (Riccuiti, 1973).

2,000 y.a. – European bison’s (Bison bonasus) range covers great European mixed temperate forests—from British Isles, across the continent into Siberia, and the Caucasus (Krasinski,1990).
8^th Century – Excessive hunting begins to contribute to decline of species (Walters, 1998).

1100 to 1500 – Urbanization of the countryside and clearing of the land for agriculture diminishes bison’s habitat and consequently, its population. Bison disappear from British Isles, Sweden, Italy, and Iberia (Krasinski,1990).

16^th & 17^th Centuries Last remaining herds of lowland subspecies exist in protected hunting preserves of Poland’s Bialowieza Forest—230 families of royal guards protect the forest (Hinrichsen, 1990).

1795 – Russia gains control of region by way of Poland’s partition. Czar Alexander I maintains hunting preserve for Russian nobility—150 guards and 34 bison specialists manage the herds (Hinrichsen, 1990). Czar removes farmers from surrounding territory to protect the forest (Riccuiti, 1973).

Early 19^th century – Only two isolated wild European subspecies exist – the lowland bison (Bison bonasus bonasus) and the Caucasus bison (Bison bonasus caucasus) living in the northwest corner of the Caucasus mountains (PHVA, 1999).

1812-3 – Records indicate about 300 to 500 lowland bison remain (Riccuiti, 1973).

1830’s - Caucasus subspecies discovered in mountain region by Black Sea Riccuiti, 1973).

1857 – Lowland bison herd increases to about 1,898. Numbers fluctuate due to browsing competition in diminishing forests from heavily stocked red deer for hunting. Also leaf-eating caterpillars periodically destroy much of the bison’s food supply. (Riccuiti, 1973).

1862 – Rebellion in the Bialowieza region decreases herd from 1,251 animals to 875 in one year (Riccuiti, 1973).

1870 – Caucasus subspecies numbers around 2,000 (Walters, 1998).

1889 – Lowland subspecies population drops to about 380 (Riccuiti, 1973).

1915 – 785 lowland bison survive (PHVA, 1999) . World War I—German troops occupy the Bialowieza area and kill close to 600 bison for meat, hides and horns (Hinrichsen, 1990). A German scientist brings to the attention of army officers animals imminent extinction. Protection set up to try to maintain herds at about 200 animals. As war comes to an end, retreating German soldiers shoot all but 9 bison (Riccuiti, 1973).

1919 - Last wild lowland bison shot by a poacher, Nikolaj Szpakowicz (Ford, 1999).

1923 – 54 bison survive in zoos and private holdings, 39 of which are traced to the Bialowieza herds. The remaining 15 consist of lowland-Caucasus hybrids (PHVA, 1999). Polish scientists, along with Swedish, German, and British colleagues, establish Society for the Protection of European Bison (Hinrichsen, 1990).

1925 – Last wild Caucasus subspecies killed (Burton & Pearson, 1987.). The animals were considered symbols of oppression by Russian revolutionaries, because they had been preserved for hunting by Russian aristocracy (Riccuiti, 1973). No pure Caucasus stock remain in wild or captivity (PHVA, 1999).

1929 – Poland buys first 2 cows from Sweden and a bull from Germany (Hinrichsen, 1990). Bison return to Bialowieza forest but remain in breeding stations (Krasinski,1990).

1930 – First calf born (Krasinski,1990).

1932 Poland declares 11,000 acres of Bialowieza forest as a national park (WCMC, 1999).

1939 – Bison numbers increased to 30 in Poland and 35 in German breeding stations. As WWII begins Polish foresters convince Russian officials to protect bison. Russians post signs in the forest that prohibits killing of bison, and make it punishable by death. One bison is killed and the three soldiers who are responsible are executed. Germans take over the area and continue prohibition on killing of bison. At the end of the war 24 bison remain in Poland and 12 in Germany. (Riccuiti, 1973).

1946 – 46 bison in Poland in breeding stations. (Riccuiti, 1973).

1952 – First two bulls released into the Bialowieza National Park (Hinrichsen, 1990). Shortly after, females are released (Riccuiti, 1973).

1957 – First reintroduced bison born in the wild. More are released from the breeding pens (Riccuiti, 1973).

1960 – 31 lowland bison exist in the wild (Riccuiti, 1973).

Today - Roughly 1,000 animals of the lowland subspecies exist and about 2,200 Caucasus hybrids (PHVA, 1999).
 

Bibliography
Books
Burton, John A. & Pearsons, Bruce. The Collins Guide to the Rare Mammals of the World. 1987. William
                Collins Sons & Co.Ltd. The Stephen Greene Press Inc., USA.
Burton, Maurice. The Animals of Europe: The Ecology of the Wildlife.1974. Harper & Row, Publishers. New York,
                Evanston, San Francisco, London.
Ricciuti, Edward R. To the Brink of Extinction. 1973. Holt, Rinehart, &Winston. New York, Chicago, San Francisco.
Savage, RJG & Long, MR. Mammal Evolution: An Illustrated Guide. 1986. Facts On File Publications. New York, NY
                &  Oxford, England.
Articles
Hinrichsen, Don. How Poland Rescued Europe’s Largest Mammal. International Wildlife. July/August 1990. v20, is4, p36.
Krasinski, Zbigniew. The Border Where the Bison Roam. Natural History. June,1990. p62.
Walters, Mark Jerome. (klj,90) Bison Country Overseas. Animals. July/August 1998. v131, is4.
Electronic Resources
World Conservation Monitoring Center. Descriptions of Natural World Heritage Properties. WCMC. 5/2/99.  http://www.wcmc.org.uk/protected_areas/data/wh/bialowieza.html
The Ultimate Ungulate Page. Your Guide to the World’s Hoofed Mammal Species. The Ultimate Ungulate Page. 5/2/99.  http://www.pathcom.com/~dhuffman/homepage.html
Ford, Peter. Wild Bison Return to Nature Preserve Inside the Bialowieza Forest.ABC News. 5/3/99.  http://more.abcnews.go.com/sections/science/DailyNews/bison980803.html
Population and Habitat Viability Assessment. European Bison. Conservation Breeding Specialist Group. 3/24/99. http://www.cbsg.org/bison.htm
Falinski, J.B. & Jedrzejewska, B.(1997). Bialowieza Primeval Forest-Basic Data.  Bialowieza National Park. 5/2/99.  http://bison.zbs.bialowieza.pl/puszcza/puszcza.htm

Pictures and Maps
Bison priscus-Cave Painting. Mammal Evolution: An Illustrated Guide. 1986.Facts On File Publications. New York, NY & Oxford, England.
Bison-Chauvet Cave Painting. Time Magazine. 2/13/95. p62,v145,n6.  Bison and Calf. Bialowieza Primeval Forest-Basic Data.Bialowieza National Park. 5/2/99. http://bison.zbs.bialowieza.pl/puszcza/puszcza.htm.
Adult Bison. Bialowieza Primeval Forest-Basic Data.  Bialowieza National Park. 5/2/99. http://bison.zbs.bialowieza.pl/puszcza/puszcza.htm
Bison Head. Descriptions of Natural World Heritage Properties. WCMC. 5/2/99.
http://www.wcmc.org.uk/protected_areas/data/wh/bialowieza.html
Bison latrifons. Mammal Evolution: An Illustrated Guide. 1986.Facts On File Publications. New York, NY & Oxford, England.
Distribution Map. The Collins Guide to the Rare Mammals of the World. 1987. William Collins Sons & Co.Ltd. The Stephen Greene Press Inc., USA.
Artiodactyl Relationships. San Francisco Zoo Docent Animal Manual. 1996.Poland Map. Polska Agencja Promocji Turystyki. 1994. Warszawa.

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